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Overview

Description

Exhilarating Power And Control: Whether its power-to-weight or power and control, the KTM 250 SX is the perfect combination of all that counts. Featuring the latest high-performance 2-stroke engine fitted within a state-of-the-art chassis, this powerhouse is undoubtedly the fastest 250cc 2-stroke on track. This proven race weapon is the right choice for those who thrive on that glorious 2-stroke sound while smashing out one hot lap after the next.

Engine & Exhaust

The engine of the KTM 250 SX features the latest 2-stroke technology with a counter-balance shaft for low engine vibration, as well as a reliable hydraulically operated DDS clutch. It has a twin-valve controlled-power-valve, which is a major factor in making the KTM 250 SX engine the most competitive 2-stroke in its class. Further refinements to the cylinder and exhaust, make powering through its 5-speed transmission a truly exhilarating experience.

Cylinder: The newly developed cylinder of the 250 SX - with a bore of 66.4mm - has all-new ports and is fitted with an overhauled power valve system. This system features a sophisticated mechanism for the lateral support exhaust ports, providing smooth and controllable power on tap. Furthermore, it's possible to change the bike's power delivery in seconds thanks to two supplied powervalve springs. Limitless settings for different tracks and preferences are up for grabs. Throw everything you have at it; new water jackets in the cylinder and head will take care of excess heat and reworked lateral cylinder head brackets allow a more efficient fixation of the engine to the frame via lightweight head stays. Yes, this is a serious piece of kit.

Crankcases and engine covers: These all-new die-cast engine cases feature an 4mm higher clutch shaft and a 19.5mm higher crankshaft, resulting in better mass centralization and quicker handling. In addition, it allows the implementation of a counter balance shaft. So your ride will be as relaxed as it is rapid. Plus, your new favorite engine will keep looking as fresh as the day you bought it with redesigned engine covers featuring a smart surface structure in order to reduce the wear caused by the rider's boots.

Transmission: A robust 5-speed transmission, its gear ratios perfectly in sync with the 250's power band. An advanced ´No Dirt´ gear shift lever design prevents mud and sand from jamming the joint of the lever and guarantees trouble-free shifting.

Balancer shaft: Say goodbye to numb feet and hands. This engine design allows the implementation of a lateral balancer shaft in order to keep the vibrations to a minimum. You know what that means: more comfort, less fatigue, more racing.

Clutch: The 250 SX employs the KTM-developed DDS clutch (damped diaphragm steel) with a wear-free steel basket and extremely heat resistant clutch plates. This clever design employs a diaphragm spring instead of the usual coil springs, making for considerably easier clutch action. A diaphragm spring also leaves sufficient space for a damping system to be integrated into the clutch hub. The goal is traction, but durability is as well. A lighter basket, a reworked inner hub and a pressure plate providing better oil supply and unsurpassed cooling up the longevity of the DDS clutch. Light operation and telepathic amounts of control are standard with this hydraulic Brembo actuated clutch.

Carburetor: The KTM 250 SX is fitted with a MIKUNI TMX carburetor. This 38mm flat slide carb lives to provide smooth and controllable power all the way up to the rev limitation. With a new intake manifold the carburetor is turned 7° in order to reduce the overflow of fuel. And it's less sensitive to different altitudes and temperatures, so you can pin it wherever, whenever.

Ignition: Its 72mm stroke is the same, the rest is brand new. The 250 SX's crank has been rebalanced, revamped and set-up with a counter balance shaft to kill vibrations, not your vibe.

Crankshaft: This reliable piece of engineering has been skillfully balanced to guarantee minimal vibrations. In its latest form, it allows a decrease of the displacement to 125cm 3 just by replacing cylinder, piston and head. There's no longer the need to change the crankshaft if you want to change displacement. Two-in-one in no time.

Cooling: KTM's proven cooling system routes the coolant from the cylinder head through the frame triangle, directly to aluminum radiators made by WP. A new filler cap system and are stiffer alloy construction increase the durability and reliability of the cooling system. Due to flow optimized internal circulation and CFD-calculated air ventilation, the system is superbly efficient. In addition, well thought-out radiator guards integrated in the front part of the shrouds provide protection in a crash.

Exhaust: The engineers meticulously tuned the resonator chamber for maximum torque and power, so this screamer is as tough as it is strong.

Chassis Features

The chassis forms an integral part of the feeling a rider has with his bike. The new chassis on the KTM 250 SX is designed to provide accurate feedback between the track and the rider, while also reducing the harshness of typical motocross terrain. The new lightweight, high-tech steel frame is made from chrome-moly and features optimized flex characteristics that soak up those big hits while also delivering excellent agility and high-speed stability. For 2019, the engine has been raised in the frame by 1° around the swing arm pivot, improving the handling and the grip of the front wheel. The refinements on this new chassis ensure the KTM 250 SX remains one of the most thrilling rides out there.

Frame: The high-tech, lightweight chrome-moly steel frame has a knack for easy handling, outlandish rideability, precise cornering and excellent stability. You can also count on high torsional rigidity and low longitudinal stiffness. This results in better absorption of the energy created from the front and rear suspension, sucking up jumps and bumps. In short: more comfort and less rider fatigue. Laterally attached, lightweight aluminum engine head stays (the connection between cylinder head and frame) contribute to precise cornering and a reduced vibration level. The engineers were able to pull off all that, while making their frame 2.2 pounds lighter than that of the lightest competitor on the market. In addition, it is easier to maintain, easier to work on and supplies more space for the tank and other components. The bike also features an extra-light subframe made of aluminum, which tiptoes the scales at less than 2 pounds.

Front suspension: All full-size SX models are fitted with the super-lightweight WP AER 48 front fork. It is a 48 mm USD air-sprung fork with separate functions for each fork leg, meaning damping functions are on the right side and the air spring is on the left. The left leg features a two-chamber system with a capsuled air cartridge, helping prevent loss of air pressure. Essentially, this means that in the rare case of a leaking outer seal, the internal cartridge pressure keeps the bike in a normal position. The air spring is exceptionally easy to use and can be adjusted to any rider weight via a single air valve and the air pump that is supplied with the bike. The right fork leg integrates a damping cartridge to fit single damping leg requirements and can be adjusted to the track conditions and the rider's preferences. (compression from top, rebound from bottom, 30 clicks each). For 2019, new settings on the damping side have improved the damping characteristics, providing great front end feel and control.

Rear suspension: The WP shock absorber has been developed with the entire frame and swingarm architecture in mind, including the linkage and the WP AER 48 front fork. It features machined and black anodized components and is a valuable, high-end product compared to roughcast reservoirs. A new, confidence inspiring setting with improved damping characteristics perfectly matches the front-end setup and its striking WP color scheme lets everyone know you have excellent taste in suspension.

Triple clamp: Top quality, CNC machined triple clamps have been a KTM trademark for years to ensure precise handling. For 2017, the upper triple clamp specifically features a redesign in conjunction with the new fork tubes. The rubber damped handlebar mount has also been reworked and the lower handlebar clamps are now separated, while on the upper side a new bridge-type clamp guarantees more torsional stiffness and can easily be replaced in case it gets twisted due to a crash. In addition, an hour meter is fitted at the upper triple clamp in order to let the rider know it's time for a service.

Brakes: You can't brake any harder, better, faster or stronger. These high-tech Brembo babies are combined with lightweight wave discs made by Galfer. For 2017, the rear brake features a 10mm longer brake pedal and you get new, less aggressive brake pads all round.

Fuel tank: A lightweight polyethylene tank with a capacity of 1.85 gallons. The fuel tank cap has an inside thread, which makes for easy and reliable closure.

Airbox: The airbox design offers maximum protection of the air filter while ensuring maximum airflow. The large twin-air filter is mounted in a stiff cage, which at the same time holds the system in place. This design is so simple you could still pop a fresh one in with a face full of mud. Without tools. In seconds.

Ergonomics & Comfort

A rider's ability to work in unison with his bike depends on how quickly and effectively he can shift his weight around the motorcycle. KTM has focused extensively on creating bodywork and ergonomics that allow for the highest levels of performance. This ensures the natural riding position offers the best possible control and, through various handlebar positions, can also be adjusted to suit every rider and condition. A rider's main connection to the motorcycle comes through the seat, footpegs and handlebars and these three touch points play a vital role in maintaining balance and control. A rider is always looking for a fast and competitive motorcycle with a great feeling of controlled agility. The 2019 KTM 250 SX, like the entire SX range, ticks all the right boxes, especially when it comes to race-ready ergonomics.

Seat: All SX models have a newly shaped seat, designed to match the improved ergonomics. The seat cover features newly developed silicone strips that provide better feel and grip for the rider. The seat is conveniently fixed to the bike using one long, lateral screw, making it safe and easy to handle.

Handlebar: KTM engineers sure know how to handle handlebars. This tapered one, made of high-strength aluminum by NEKEN, is fixed in damped rubber mounts and has two different positions. From 2017 onwards, the lower handlebar clamps are separated, while on the upper side a new bridge-type clamp guarantees more torsional stiffness. It's also easier to replace the bar in case it gets twisted in a nasty crash. ODI lock-on grips make grip changes easy which does not require any wire or glue to be secured.

Footpegs: Sophisticated ´No Dirt´ footpegs prevent smudging up the pegs, even when digging in deep ruts. Looking for a higher riding position? Then just mount the footpegs of the 2018 EXC models, which are 6mm higher than the SX versions.

Bodywork & Graphics

The KTM 250 SX has become an icon amongst 2-stroke fanatics, but for this bike, the classic sound it produces is where the nostalgia ends. A combined effort between KTM's factory riders, KTM R&D and Kiska Design has resulted in a highly effective modern-looking motorcycle with bodywork that achieves complete harmony between rider and bike. When designing the 2019 SX range, the main goal was to provide the perfect contact points for the rider, allowing maximum freedom of movement and improved motorcycle control. Examples of the intelligent design can be seen in the Ibeam structure of the front and rear fenders, which guarantee maximum stability and the lowest possible weight. The modern design and graphics ensure that it is not only about function, but an impressively fast and aggressive look that sends a clear message to the competition.

Decals: New graphics convey the READY TO RACE character of the 2017 SX model line.

Software & Electronics

Absolute performance purity is the name of the game when it comes to electronics and the new KTM 250 SX. Undiluted 2-stroke simplicity, with an hour meter to keep a check on how long you've been shredding and an optional rev counter to assist with perfect setup.

Engine

Design: 1-cylinder, 2-stroke engine

Displacement: 249 cm³

Bore: 66.4 mm

Stroke: 72 mm

Starter: Kickstarter

Transmission: 5-speed

Clutch: Wet multi-disc clutch, hydraulically actuated

EMS: Kokusan

Chassis

Frame design: 25CrMo4 steel central-tube frame

Front suspension: WP-USD, AER 48, Ø 48 mm

Rear suspension: WP shock absorber with linkage

Front brake: Disc brake

Rear brake: Disc brake

Front brake disc diameter: 220 mm

Rear brake disc diameter: 220 mm

Chain: 5/8 x 1/4"

Steering head angle: 63.9 °

NOTES:

The illustrated vehicles may vary in selected details from the production models and some illustrations feature optional equipment available at additional cost. All information concerning the scope of supply, appearance, services, dimensions and weights is non-binding and specified with the proviso that mistakes, printing, setting and typing errors may occur; such information is subject to change without notice. No rights may be derived from incorrect statements.